The present invention relates to a laser projection display device in which light emitted from a light source such as semiconductor laser is scanned by a two-dimensional scanning mirror such as a MEMS mirror to display an image, and relates to drive control of a laser diode that emits image light.
In recent years, a small-sized projector that uses MEMS technology and a semiconductor laser light source has been widely used. For example, Japanese Unexamined Patent Application Publication No. 2006-343397 and Japanese Unexamined Patent Application Publication No. 2003-5714 disclose a projector that projects a picture by scanning a biaxial MEMS mirror or a biaxial MEMS scanner horizontally and vertically, and at the same time, by modulating a laser light source. A small-sized projector that uses semiconductor laser as described above has a problem in that, because the forward current vs. light amount characteristic of a laser diode used in this projector changes in accordance with the load variation and ambient temperature, the white balance of the display screen changes.
Japanese Unexamined Patent Application Publication No. 2003-5714 proposes a projector that is configured in such a way that a partially-reflecting mirror spatially separates a part of laser light, and temperature compensation is performed by detecting each color of the part of laser light to keep the white balance constant.